1. Field of the Invention
The present invention relates to a capacitor, and particularly to an embedded capacitor mounted onto a printed circuit board.
2. Description of the Related Art
Electronic components, such as ICs, resistances, capacitors, and inductors, etc., are typically integrated on a printed circuit board. In contrast, an embedded printed circuit having embedded components mounted thereon do not mount any electronic parts through soldering. Instead, the space between embedded components that are stacked on the embedded printed circuit board is filled with conductive material. Thus, the embedded printed circuit board has an advantage in that more parts can be mounted in a small volume compared with a general printed circuit board.
The embedded printed circuit boards are applied to potable electronic products. The embedded printed circuit board may include embedded components, such as resistances, capacitors, inductors, etc. The capacitor accomplishes various functions such as suppression, turning, decoupling, bypassing, and frequency determination, etc.
As the embedded components and the embedded printed circuit boards are becoming popular, the capacitance required for the embedded capacitor is also increased. The embedded capacitor comprises copper films opposing each other and a dielectric layer positioned between the copper films. The capacitance of the embedded capacitor is determined according to the dielectric constant of the dielectric layer, and the area of the copper films, etc.
A dielectric medium of a high dielectric constant must be used or the area of the copper film must be increased, in order to increase the dielectric constant of the embedded constant. When the copper film is actually increased, the dielectric constant of the embedded capacitor is increased but the size of the embedded capacitor is also increased. This is not suitable for the electronic circuit which uses the embedded printed circuit board. Alternatively, the dielectric medium of a high dielectric constant can be used to increase the dielectric constant.
However, the printed circuit board has a structure in which electrode patterns made of a metal are formed on an organic material, which tend to damage at temperature of 250 degrees Celsius during the manufacturing process. Namely, the embedded capacitor which comprises a dielectric medium of a high dielectric constant undergoes a process that require a pressing between the copper films at a high temperature, but the embedded capacitor can not endure the high temperature process.